Yambits swingarm needle bearings

[voelser]

Does any of my fellow UK builders have any experience with these? I'm having some trouble with them:

Initially I couldn't drive the bearings in deep enough for the dustcap holder to sit flush, but after going to a garage to have them pressed in deeper the two inner needle bearings seem to jam the axle tube!

All I can think of is that they either slightly buckled or that the tube in the swingarm which holds the bearing isn't perfectly cylindrical towards the end and by pressing them in that deep the ends get pinched together.

So far the only solutions I have come up with:

1. drive them out, bin them, buy a new set and try again. Apart from the added cost, there is of course the risk of it happening again.

2. Removing the needles of the inner bearings and making sure the collars don't catch the axletube and using only the outer bearings. I figure as it didn't have any bearings at all before, this may be possible?

Any other ideas or suggestions?

Thanks!

 

[fredintoon]

Hi voelser,
with headrace bearings low friction rules but ordinarily I don't like using rolling element bearings on anything that don't turn through more than a half-circle and the swingarm turns far less than that.
IMHO plain bearings are the way to go for a swingarm.
However, the stock XS650 swingarm pivot design relies on preventing that thin walled bearing sleeve from turning by pinching it in the frame by tightening the through bolt.
All the XS650 swingarms I've fixed have had the through bolt work loose over time so the sleeve turned with the swingarm and the de-facto bearing was between the sleeve's inner diameter and the through bolt outer surface.
As these two surfaces were never intended to be a bearing they don't have the necessary fit or surface to be one which may explain why an XS650 with some miles on it don't handle as well as it used to.
OK then, what to do about it?
My fixes have been to change the plastic bushes for bronze ones, replace the stock stepped down through bolt with a full M16 one from MikesXS, careful re-assembly and re-torquing the through bolt at regular intervals as I pump more grease in there.
But I shouldn't have to eff around like that.
How about this?
Re-bush with the bronze bearings.
Get a hardened & ground through bolt made that fits the bushings.
Drill, cross-drill & tap it for a grease nipple.
Drill the frame out to fit the bigger through bolt and move the stop block to match.
Tension the through bolt with a nylok nut.